Fujitsu 8FX User Manual

MB95630H Series
488 FUJITSU SEMICONDUCTOR LIMITED MN702-00009-2v0-E
CHAPTER 23 UART/SIO DEDICATED BAUD RATE GENERATOR
23.3 Operations
23.3 Operations
The UART/SIO dedicated baud rate generator serves as the baud rate generator
in clock asynchronous mode (UART).
■ Baud Rate Setting
The CKS bit in the SMC1n register of the UART/SIO is used to select the serial clock. This
selects the UART/SIO dedicated baud rate generator.
In asynchronous clock mode, the shift clock that is selected by the CKS bit and divided by four
is used and transfers can be performed within the range from −3% to +3%. The baud rate
calculation formula for the UART/SIO dedicated baud rate generator is shown below.
Figure 23.3-1 Baud Rate Calculation Formula when UART/SIO Dedicated Baud Rate Generator
Is Used
The baud rate can be set in UART mode within the following range.
Table 23.3-1 Sample Asynchronous Transfer Rates by Baud Rate Generator
(Machine Clock = 10 MHz, 16 MHz, 16.25 MHz)
UART/SIO dedicated baud rate
generator setting
UART
internal
division
Total division ratio
(PSS × BRS × 4)
Baud rate
(10 MHz /
Total division
ratio)
Baud rate
(16 MHz /
Total division
ratio)
Baud rate
(16.25 MHz /
Total division
ratio)
Prescaler select
PSS[1:0]
Baud rate counter
setting BRS [7:0]
1 (Setting value: 0, 0) 20 4 80 125000 200000 203125
1 (Setting value: 0, 0) 22 4 88 113636 181818 184659
1 (Setting value: 0, 0) 44 4 176 56818 90909 92330
1 (Setting value: 0, 0) 87 4 348 28736 45977 46695
1 (Setting value: 0, 0) 130 4 520 19231 30769 31250
2 (Setting value: 0, 1) 130 4 1040 9615 15385 15625
4 (Setting value: 1, 0) 130 4 2080 4808 7692 7813
8 (Setting value: 1, 1) 130 4 4160 2404 3846 3906
Baud rate =
Machine clock (MCLK)
[bps]
4
×
×
1
2
4
8
2
:
255
UART dedicated baud rate generator baud
rate setting register ch. n (BRSRn)
Baud rate setting (BRS[7:0])
UART dedicated baud rate generator
prescaler select register ch. n (PSSRn)
Prescaler select (PSS[1:0])
Table 23.3-2 Baud Rate Setting Range in Clock Asynchronous Mode (UART)
PSS[1:0] BRS[7:0]
0b00 to 0b11 0x02 (2) to 0xFF (255)

Fujitsu 8FX Specifications

General

Brand	Fujitsu
Model	8FX
Category	Computer Hardware
Language	English